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PDFのパスワード解除

Remove a known PDF password. Files and passwords never leave your browser.

🔒Local processing – No upload
This tool is only for PDF files you own or are authorized to process. You must know the current password. Qudo does not crack, guess, or bypass unknown passwords.

Drop PDF files here or click to browse

Select one or more password-protected PDF files

Max 200 MB per file · Up to 20 PDFs · 500 MB total

Please select at least one PDF file

Your files and passwords never leave this browser tab.

What is PDF Unlock?

This tool removes the open password from PDF files that you already know the password for. Once unlocked, the new PDF can be opened directly without entering a password. All processing happens in your browser – no files or passwords are uploaded to any server.

How to Unlock a PDF

  1. Upload one or more password-protected PDF files.
  2. Enter the current correct password for each file (or one password for all).
  3. Confirm that you own the files or have authorization.
  4. Click "Unlock PDF" to start processing.
  5. Download the unlocked PDF – it will open without a password.

What This Tool Cannot Do

Qudo cannot crack or guess unknown passwords, bypass document permissions without the password, recover forgotten passwords, restore corrupted PDFs, or guarantee support for every encryption format. This tool does not provide signature identity verification.

Local Processing

Your PDF files and passwords are processed entirely within your browser. Nothing is uploaded to Qudo servers. No passwords are stored, logged, or sent to analytics services.

Impact of Removing Password

Once unlocked, the output file can be opened by anyone who receives it. Existing digital signatures may become invalid. The original encrypted file is not modified. Removing a password does not automatically delete PDF metadata or sensitive content. We recommend keeping a copy of the original encrypted file.

Limitations

This tool supports most standard PDF encryption methods (RC4, AES-128, AES-256). It does not support certificate-based encryption or corrupted files. Very large files may be limited by your browser’s available memory.

Privacy

Files and passwords never leave your browser. Qudo does not store, log, or transmit any passwords or file content. After processing, password fields and temporary data are cleared from the page.

Frequently Asked Questions

Can Qudo crack a forgotten PDF password?▼
No. Qudo does not crack, guess, or brute-force unknown passwords. You must provide the current correct password.
Do I need to know the current password?▼
Yes. You must enter the correct open password for each PDF. This tool cannot bypass or recover unknown passwords.
Are PDF files and passwords uploaded?▼
No. All processing happens locally in your browser. Nothing is sent to any server.
Can I unlock multiple PDFs at once?▼
Yes. You can upload up to 20 PDF files and process them in a single batch.
Can different PDFs use different passwords?▼
Yes. You can switch to per-file password mode and enter a separate password for each file.
Why does it say the password is wrong?▼
The password you entered does not match the PDF’s open password. Please check for typos, case sensitivity, and try again.
Why can’t some PDFs be processed?▼
The PDF may use an unsupported encryption method, be corrupted, or not require a password at all.
Does unlocking reduce PDF quality?▼
No under normal circumstances. This tool removes encryption directly without re-rendering pages as images.
Are digital signatures still valid after unlocking?▼
Not necessarily. Removing encryption and rewriting the file may invalidate existing digital signatures. Keep a copy of the original.
Do unencrypted PDFs need processing?▼
No. If a PDF has no password, it will be detected and skipped automatically.
Does unlocking remove PDF metadata?▼
No. Removing the password does not automatically delete metadata. Use the PDF Metadata tool to clean metadata separately.
Can I use this on a phone?▼
Yes. The tool works on mobile browsers that support WebAssembly.
Is the unlocked PDF safe?▼
The unlocked file can be opened without a password. Only save it to trusted devices and share it carefully.
What is the difference between owner and open passwords?▼
An open password is required to view the PDF. An owner password controls permissions like printing or copying. This tool removes the open password.
Does Qudo store my password?▼
No. Passwords are used only in browser memory during processing and are cleared when you finish or close the page.

Related Tools

After processing, Qudo clears password fields, temporary files, and accessible memory references where possible. Browser memory management prevents web applications from guaranteeing physical memory erasure.